Sums to 5: If you know the sums to 5, like 3+2, you can find other sums like 3+4, because 3+4 = 3+2 plus 2 more Sums to 10: If you know that 6+4 = 10, then you can figure out 6+5, because it’s 1 more than 6+4 Ten-frame cards are great for learning sums to 10. See how to use them at this website. Doubles plus one: 6+7 = (6+6) + 1 more Doubles plus two: 7+9 = (7+7) + 2 more Nines: Add ten then subtract 1
Strategies for multiplying
x 0: any number times zero is zero x 1: any number times 1 is itself x 2: doubles – skip count by 2’s – all the even numbers x 3: skip count by 3’s x 4: double doubles x 5: times 10, then half (e.g. 6 x 5 is 6 x 10, then half of that) x 6, 7, 8: many of these are found by the commutative property (e.g. 6 x 4 = 4 x 6 – then use the strategy for 4’s) squares: these are easy and fun to remember (2x2=4, 3x3=9, 4x4=16, etc.) near neighbors: square - 1 (for any two numbers that are off by two, take the square of the number between them, then subtract 1, e.g. 7 x 5 = 6 x 6 - 1) x 9: the finger method, or remember that the sum of all multiples of 9 is 9. (18 is 1+8, 27 is 2+7, 36 is 3+6 etc.)
Strategies for adding
Sums to 5: If you know the sums to 5, like 3+2, you can find other sums like 3+4, because 3+4 = 3+2 plus 2 more
Sums to 10: If you know that 6+4 = 10, then you can figure out 6+5, because it’s 1 more than 6+4
Doubles plus one: 6+7 = (6+6) + 1 more
Doubles plus two: 7+9 = (7+7) + 2 more
Nines: Add ten then subtract 1
Strategies for multiplying
x 0: any number times zero is zero
x 1: any number times 1 is itself
x 2: doubles – skip count by 2’s – all the even numbers
x 3: skip count by 3’s
x 4: double doubles
x 5: times 10, then half (e.g. 6 x 5 is 6 x 10, then half of that)
x 6, 7, 8: many of these are found by the commutative property (e.g. 6 x 4 = 4 x 6 – then use the strategy for 4’s)
squares: these are easy and fun to remember (2x2=4, 3x3=9, 4x4=16, etc.)
near neighbors: square - 1 (for any two numbers that are off by two, take the square of the number between them, then subtract 1, e.g. 7 x 5 = 6 x 6 - 1)
x 9: the finger method, or remember that the sum of all multiples of 9 is 9. (18 is 1+8, 27 is 2+7, 36 is 3+6 etc.)